> On 11-Jun-2020, at 8:03 PM, Philip Race <philip.r...@oracle.com> wrote:
>
>
>
> On 6/11/20, 1:57 AM, Jayathirth D v wrote:
>>
>> Hi Phil,
>>
>> I tried tested the fix in my Windows 10 machine with Intel integrated UHD
>> Graphics 620.
>>
>> LargeWindowPaintTest.java passes with/without fix in my machine.
>> AlphaPrintTest.java without fix just opens up blank frame without any
>> instructions and with fix it shows instructions for the test.
>> Is this expected behaviour?
>
> I guess this is a conseqeuence of the on-screen bug ! Which in contrast to
> the LargeWindowPaintTest affects you.
>
> Without the fix the window is too big and you have an intel chip so you are
> going through the GDI path.
Okay
>>
>> AlphaPrintTest.java with fix when it shows instructions if I click on
>> Pass(Since I don’t have printer right now) it doesn’t pass/close the window.
>> Only after I click on Print button and then close print dialog it allows me
>> to click on Pass button.
>>
> Well .. perhaps I should add an @requires printer on this test ?
> But can't you print to file using Windows built in print to pdf ?
Yes I can. And as Kevin mentioned it is good that we enforce and try to print
it. So looks okay.
>> Also how does these tests behave in our internal CI machines?
> The printing one is manual so it is never going to pass there.
>
> -phil
>>
>> Thanks,
>> Jay
>>
>>> On 11-Jun-2020, at 2:18 AM, Philip Race <philip.r...@oracle.com
>>> <mailto:philip.r...@oracle.com>> wrote:
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8240654
>>> <https://bugs.openjdk.java.net/browse/JDK-8240654>
>>> Webrev: http://cr.openjdk.java.net/~prr/8240654/index.html
>>> <http://cr.openjdk.java.net/%7Eprr/8240654/index.html>
>>>
>>> This is for JDK 15 so review ASAP please since RDP 1 and the test cycle are
>>> looming.
>>>
>>> This is not a fix for a JDK bug. It is a bunch of workarounds for a
>>> Microsoft Windows bug affecting
>>> GDI in the context of ZGC (http://openjdk.java.net/jeps/333
>>> <http://openjdk.java.net/jeps/333>).
>>> Some extra details about the Windows bug at the end, but first the
>>> technical details of the fix.
>>>
>>> With ZGC's memory allocation requirement of reserving memory in 2Mb chunks
>>> some Windows GDI
>>> functions, mostly involving some bitmaps APIs may return a failure code (ie
>>> fail!)
>>> This typically occurs when Java heap memory is used for a Java image and
>>> then in a JNI
>>> call we use GetPrimitiveArrayCritical so that Java heap allocated memory is
>>> passed to a GDI
>>> function AND the Java heap memory spans one of the 2Mb boundaries.
>>> This is very easy to trigger in almost any Java UI app if the window is of
>>> a large enough (ie typical) size.
>>> NB: if you have an Nvidia or ATI card, then you won't see it, because the
>>> D3D pipeline doesn't
>>> call the affected method but if you have an Intel chip as do 90% (?) of
>>> laptops you will see it.
>>> There are also several other places we found that are affected. Printing is
>>> the other one
>>> somewhat easy to trigger. The others : custom cursors and tray icons are
>>> less common.
>>> The painful thing here is that there is no definitive list (a list of the
>>> known ones is below) of
>>> affected Windows GDI APIs and we are just hunting around our code trying to
>>> see where it
>>> might be side-swiped by this bug.
>>>
>>> The basic approach in these workarounds is that for cases where performance
>>> does not matter we now copy
>>> and for cases where performance does matter or larger amounts of memory is
>>> involved we check if
>>> the return value of the GDI function indicates failure and then re-try with
>>> a copy of the heap memory.
>>> Unless GDI was randomly failing already (unlikely) this should be a no-risk
>>> solution in the high profile cases.
>>> We have done performance measurements on the important screen case and the
>>> failures
>>> happen fast so the penalty is then in the re-try which is only if ZGC is
>>> enabled.
>>> Always copying the memory is slower (and memcpy is the slow operation) than
>>> an alternative approach
>>> that "knows" about the memory allocation of ZGC but this coupling and the
>>> complexity seem like they aren't
>>> worth it since I haven't seen any visible performance consequence. That can
>>> be revisited
>>> some day if need be, but for now we have correctness which is the key as
>>> well as sufficient performance.
>>>
>>> I've created an automated test for the most important on-screen case.
>>> Also a manual printing test case which invokes ZGC is provided since there
>>> we also only
>>> conditionally copy. In the other cases we now always copy so existing test
>>> cases should over those.
>>>
>>> There is some clean up in this fix - one completely unused (provably so
>>> because it was #if'd out)
>>> JNI method in awt_PrintJob.cpp is removed since it had code that looked
>>> like it needed a workaround,
>>> which would be somewhat of a waste of effort.
>>>
>>> the doPrintBand code and its callee bitsToDevice has code I think we can
>>> remove too since
>>> I don't see how it ever gets executed (the top down case for browserPrint
>>> == true) but
>>> I think I'll save that for a P4 follow-on since it does nothing that would
>>> be affected by this
>>> Windows bug.
>>>
>>> One oddity is the in the printing case I observed that some times the
>>> rendering is performed
>>> even if an error code is returned. I don't know why, but in code we can't
>>> tell that it was actually
>>> rendered and in any case there is no harm in repeating the call with copied
>>> memory.
>>>
>>> We are right before the JDK15 stabilisation fork and this fix needs to go
>>> there and will
>>> but the webrev is against jdk/client simply because jdk15 does not exist
>>> yet !
>>>
>>> Please test and review ASAP.
>>>
>>> About the bug:
>>> Microsoft has acknowleged the bug and will publish a knowledge base article
>>> about it
>>> but a fix may show up only in a future version of Windows. Not, it seems,
>>> any time soon.
>>> Below is a list of potentially affected GDI APIs. Per microsoft whether it
>>> actually manifests in
>>> any specific case depends on "branching"
>>> https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/checkbitmapbits
>>>
>>> <https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/checkbitmapbits>
>>> https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/createcolortransform
>>>
>>> <https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/createcolortransform>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setdibitstodevice
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setdibitstodevice>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-stretchdibits
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-stretchdibits>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getbitmapbits
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getbitmapbits>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibitmap
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibitmap>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-polydraw
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-polydraw>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-drawescape
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-drawescape>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createbitmap
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createbitmap>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setbitmapbits
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setbitmapbits>
>>> https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getdibits
>>>
>>> <https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getdibits>
>>>
>>> -phil.
>>>
>>
